How to use engine mode? Hybrid wont charge battery keeps going to 1 bar occasionally wont start.

Discussion in 'Gen 2 Prius Technical Discussion' started by iamerror, Aug 12, 2025 at 8:41 PM.

  1. iamerror

    iamerror New Member

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    My mom has one and it wont start it only has one bar. For some reason it will let the main battery go all the way down to 1 bar and then wont start or go or anything. Idk why it doesn't use the engine to charge it up when it gets low like this.

    We know the battery is old but toyota dealership last told us the main battery looks fine. But when he was looking at it, we drove from the high way and it was like 50 to 80% full. This was a month or so ago. It was brought there because it had to be towed, but then started working so we drove it up there but they looked at it and said it was fine.

    Anyways it wont start right now. As mentioned, it's done this once before. Then started working like it was totally fine. Not sure why this happens. When possible I will try to have a youtube video made. I'm not there, she just told me about this and so I made an account here to try to figure out what is wrong with it. I think it's a 2008.
     
    #1 iamerror, Aug 12, 2025 at 8:41 PM
  2. Tombukt2

    Tombukt2 Senior Member

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    Yeah all this can be very subjective folks are talking about driving around on electricity and all this kind of stuff. Once you get to the nitty gritty it's something pretty basic usually or you're an out lier and have internal hybrid synergy drive issues open short in trans motors etc . Extremely rare . These threads generally go 50 plus posts deep .
     
    #2 Tombukt2, Aug 13, 2025 at 6:12 AM
  3. Brian1954

    Brian1954 Senior Member

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    The first thing to check for a no start condition is the 12v battery.
     
    #3 Brian1954, Aug 13, 2025 at 8:29 AM
    BiomedO1 likes this.
  4. BiomedO1

    BiomedO1 Senior Member

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    ^+1, Yep, I'd start with the 12V aux. battery - it's probably borderline. I'm assuming that there's no CEL since a Toyota technician looked at it? Obviously not a very good technician, because they didn't even check the 12V battery condition.

    1. you can try jump starting the car.
    2. pull out he 12V battery and take it down to any auto parts store for testing. It's located in rear passenger trunk panel.

    Hope this helps..
     
    #4 BiomedO1, Aug 13, 2025 at 9:25 AM
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